时间状语从句,when和while用法区分.
她正在打信的时候,老板到了.
打信是个时间段,可以用when也可以用while.
When she was typing a letter,the boss arrived.
While she was typing a letter,the boss arrived.
我正要离开家时,邮递员到了.
离开家时个时间点,只能用when.
When I leaving the house,the postman arrived.